/*
 * Copyright (C) 2008 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.zxing.client.android;

import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
import org.apache.http.HttpRequestInterceptor;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.client.params.HttpClientParams;
import org.apache.http.client.protocol.ClientContext;
import org.apache.http.conn.ClientConnectionManager;
import org.apache.http.conn.scheme.PlainSocketFactory;
import org.apache.http.conn.scheme.Scheme;
import org.apache.http.conn.scheme.SchemeRegistry;
import org.apache.http.conn.ssl.SSLSocketFactory;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
import org.apache.http.params.HttpProtocolParams;
import org.apache.http.protocol.BasicHttpContext;
import org.apache.http.protocol.BasicHttpProcessor;
import org.apache.http.protocol.HttpContext;

import java.io.IOException;

/**
 * <p>Subclass of the Apache {@link DefaultHttpClient} that is configured with
 * reasonable default settings and registered schemes for Android, and
 * also lets the user add {@link HttpRequestInterceptor} classes.
 * Don't create this directly, use the {@link #newInstance} factory method.</p>
 * <p/>
 * <p>This client processes cookies but does not retain them by default.
 * To retain cookies, simply add a cookie store to the HttpContext:
 * <pre>context.setAttribute(ClientContext.COOKIE_STORE, cookieStore);</pre>
 * </p>
 */
public final class AndroidHttpClient implements HttpClient {

	/**
	 * Set if HTTP requests are blocked from being executed on this thread
	 */
	private static final ThreadLocal<Boolean> sThreadBlocked =
		new ThreadLocal<Boolean>();

	/**
	 * Interceptor throws an exception if the executing thread is blocked
	 */
	private static final HttpRequestInterceptor sThreadCheckInterceptor =
		new HttpRequestInterceptor() {
			public void process(HttpRequest request, HttpContext context) {
				if (Boolean.TRUE.equals(sThreadBlocked.get())) {
					throw new RuntimeException("This thread forbids HTTP requests");
				}
			}
		};

	/**
	 * Create a new HttpClient with reasonable defaults (which you can update).
	 *
	 * @param userAgent to report in your HTTP requests.
	 * @return AndroidHttpClient for you to use for all your requests.
	 */
	public static AndroidHttpClient newInstance(String userAgent) {
		HttpParams params = new BasicHttpParams();

		// Turn off stale checking.  Our connections break all the time anyway,
		// and it's not worth it to pay the penalty of checking every time.
		HttpConnectionParams.setStaleCheckingEnabled(params, false);

		// Default connection and socket timeout of 20 seconds.  Tweak to taste.
		HttpConnectionParams.setConnectionTimeout(params, 20 * 1000);
		HttpConnectionParams.setSoTimeout(params, 20 * 1000);
		HttpConnectionParams.setSocketBufferSize(params, 8192);

		// Don't handle redirects -- return them to the caller.  Our code
		// often wants to re-POST after a redirect, which we must do ourselves.
		HttpClientParams.setRedirecting(params, false);

		// Set the specified user agent and register standard protocols.
		HttpProtocolParams.setUserAgent(params, userAgent);
		SchemeRegistry schemeRegistry = new SchemeRegistry();
		schemeRegistry.register(new Scheme("http",
			PlainSocketFactory.getSocketFactory(), 80));
		schemeRegistry.register(new Scheme("https",
			SSLSocketFactory.getSocketFactory(), 443));
		ClientConnectionManager manager =
			new ThreadSafeClientConnManager(params, schemeRegistry);

		// We use a factory method to modify superclass initialization
		// parameters without the funny call-a-static-method dance.
		return new AndroidHttpClient(manager, params);
	}

	private final HttpClient delegate;

	private AndroidHttpClient(ClientConnectionManager ccm, HttpParams params) {
		this.delegate = new DefaultHttpClient(ccm, params) {
			@Override
			protected BasicHttpProcessor createHttpProcessor() {
				// Add interceptor to prevent making requests from main thread.
				BasicHttpProcessor processor = super.createHttpProcessor();
				processor.addRequestInterceptor(sThreadCheckInterceptor);
				return processor;
			}

			@Override
			protected HttpContext createHttpContext() {
				// Same as DefaultHttpClient.createHttpContext() minus the
				// cookie store.
				HttpContext context = new BasicHttpContext();
				context.setAttribute(ClientContext.AUTHSCHEME_REGISTRY, getAuthSchemes());
				context.setAttribute(ClientContext.COOKIESPEC_REGISTRY, getCookieSpecs());
				context.setAttribute(ClientContext.CREDS_PROVIDER, getCredentialsProvider());
				return context;
			}
		};
	}

	/**
	 * Release resources associated with this client.  You must call this,
	 * or significant resources (sockets and memory) may be leaked.
	 */
	public void close() {
		getConnectionManager().shutdown();
	}

	public HttpParams getParams() {
		return delegate.getParams();
	}

	public ClientConnectionManager getConnectionManager() {
		return delegate.getConnectionManager();
	}

	public HttpResponse execute(HttpUriRequest request) throws IOException {
		return delegate.execute(request);
	}

	public HttpResponse execute(HttpUriRequest request, HttpContext context) throws IOException {
		return delegate.execute(request, context);
	}

	public HttpResponse execute(HttpHost target, HttpRequest request) throws IOException {
		return delegate.execute(target, request);
	}

	public HttpResponse execute(HttpHost target, HttpRequest request,
								HttpContext context) throws IOException {
		return delegate.execute(target, request, context);
	}

	public <T> T execute(HttpUriRequest request, ResponseHandler<? extends T> responseHandler) throws IOException {
		return delegate.execute(request, responseHandler);
	}

	public <T> T execute(HttpUriRequest request, ResponseHandler<? extends T> responseHandler, HttpContext context)
		throws IOException {
		return delegate.execute(request, responseHandler, context);
	}

	public <T> T execute(HttpHost target, HttpRequest request, ResponseHandler<? extends T> responseHandler)
		throws IOException {
		return delegate.execute(target, request, responseHandler);
	}

	public <T> T execute(HttpHost target, HttpRequest request,
						ResponseHandler<? extends T> responseHandler,
						HttpContext context)
		throws IOException {
		return delegate.execute(target, request, responseHandler, context);
	}

}
